Hydraulic filter with one-piece input end cap

ABSTRACT

A hydraulic filter includes a canister extending along the longitudinal axis. A closed end cap is at one end of the canister for closing one end thereof. A removable filter element is contained within the canister and a modular one-piece input end cap is at an end of the canister. The one-piece input end cap includes a hydraulic input chamber and a hydraulic output chamber which can be positioned in any one of three mutually perpendicular directions. The one-piece input end cap also allows for sensors to be positioned in any one of three mutually perpendicular directions. In addition, the one-piece input end cap can be utilized in base-ported or top-ported configurations while also allowing for side-to-side or side-to-end configurations.

CROSS REFERENCE TO RELATED APPLICATION

The present invention claims priority as a Divisional of U.S. patentapplication Ser. No. 12/581,226, filed Oct. 19, 2009, entitled“Hydraulic Filter with Modular One-Piece Input End Cap”, which publishedon Feb. 11, 2010 as U.S. Published Patent Application Number2010-0032361 which is incorporated herein by reference. U.S. patentapplication Ser. No. 12/581,226, is a Divisional of U.S. patentapplication Ser. No. 10/360,590 filed Feb. 7, 2003, now U.S. Pat. No.7,604,738, which issued Oct. 20, 2009, and which is incorporated hereinby reference. U.S. patent application Ser. No. 10/360,590 claimspriority from U.S. Provisional Patent Application Ser. No. 60/355,237,filed Feb. 8, 2002 entitled “Hydraulic Filter with Modular One-PieceInput End Cap”, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hydraulic filter and, moreparticularly, to a one-piece input end cap, such as a base or top of afilter; this one-piece input end cap having the ability to providemultiple porting options, mounting options, sensor placements, andfiltration system configurations.

2. Description of the Prior Art

Filters are generally comprised of a housing with one or more fluidinlets and one or more fluid outlets and a filter element contained in ahousing. The housing is often formed of a canister and two end caps.Multiple filters have been combined in series and in parallel to formspecific filtration systems. In certain applications, a single filtercan also form the entire filtration system.

Filtration systems today are used in a variety of applications and mostoften are built or modified from the original configuration toaccommodate the engineering limitations of each situation. Commonly,filters of such filtration systems have to be uniquely designed tosatisfy design configurations, such as fluid inlet and outlet locationsor sensor locations. Due to such demands, manufacturers are oftenrequired to design specific filters for each individual application.This, in turn, involves additional engineering steps, such as developingand manufacturing new castings for each new filter.

As can be seen, this method of having to produce a new filter toaccommodate these different circumstances tends to be inefficient intime and cost. Not only would long periods of time have to be allocatedfor the design process of the filters and associated filtration systems,but also for the manufacturing process for the filters which, in turn,would quickly increase the cost of the product. Additionally, thisprocess would prove to be inefficient due to low turnaround andinventory stagnation. This proves to be a cumbersome practice and canalso be detrimental to a company's competitiveness and sustainabilitydue to longer lead times and the inability to meet demand.

It is, therefore, an object of the present invention to create anefficient filter that allows for the necessary flexibility required indifferent applications and in design configurations, for example, theability for the filters to be easily placed in series or parallel.

SUMMARY OF THE INVENTION

The above objects are achieved with a filter according to the presentinvention. The filter according to the present invention will include acanister extending along a longitudinal axis with a closed end cap atone end of the canister attached thereto and housing a removable filterelement within the canister. A one-piece input end cap is at an oppositeend of the canister from the closed end cap and attached to thecanister. The one-piece input end cap includes a hydraulic input chamberextending to the filter element (generally the outside of a tubularfilter element) and configured, for example, by machining, to be portedto an input port connector from any of three mutually perpendiculardirections. The one-piece input end cap additionally includes ahydraulic output chamber extending from the filter element andconfigured to be ported to an output connector from any of threemutually perpendicular directions.

One embodiment of the present invention preferably includes a sensor,such as a differential pressure sensor, mounted in either the hydraulicinput chamber and/or the hydraulic output chamber and adapted to extendfrom any of three mutually perpendicular directions from the modularone-piece input end cap.

In one embodiment of the present invention, a filtration system can beprovided with individual filters adjacent and mounted directly to eachother in any of two mutually perpendicular directions. The adjacentfilters preferably are connected to a pump and have the ability to beconnected either in series or parallel.

The present invention preferably provides a modular one-piece input endcap which includes substantially rectangular mounting flanges extendingthe width of the modular one-piece input end cap on opposite sides ofthe input end cap where one mounting flange provides a hydraulic portfor the hydraulic input chamber and the other mounting plate provides ahydraulic port for the hydraulic output chamber. Additionally, themodular one-piece input end cap may include a pair of bosses on oppositeends of the modular one-piece input end cap. The pair of bosses islocated in a position substantially perpendicular to the mounting platesand wherein one boss provides a hydraulic port for the hydraulic inputchamber and the other boss provides a hydraulic port for the hydraulicoutput chamber. Further, the modular one-piece input end cap may includea cylindrical member having an axis co-linear with the axis of thecanister and internal threads for attaching the canister thereto.

Another embodiment of the present invention preferably includes amanifold assembly formed integrally with the modular one-piece input endcap. The modular one-piece input end cap of the present invention may beutilized in base-ported filters or top-ported filters.

According to a preferred embodiment, a connecting end cap for a filteris provided. The filter comprises a cylindrical canister having acylindrical axis, and a tubular filter element. The connecting end capand a closed end cap are arranged such that the tubular filter elementrests within the canister. The closed end cap seals one end of thefilter element and the connecting end cap directs input flow to theexterior of the tubular filter element and output flow from the interiorof the tubular filter element. The connecting end cap comprises acup-shaped body defined by a cylindrical wall having a cylindrical axisthe same as the cylindrical axis of the canister. The open end of thecylindrical wall is sized to receive the cylindrical canister and theclosed end of the cup shaped body is defined by a wall perpendicular tothe cylindrical axis. The connecting end cap has an input and an outputchamber adjacent the closed end. The input and output chambers areseparated by a wall positioned so that the inlet chamber abuts two portpositions on the cylindrical wall 90 degrees apart around thecylindrical axis and such that the outlet chamber abuts two outlet portpositions 180 degrees across from the inlet port positions. The outletport chamber is further enclosed by an interior wall generally parallelto the end wall and spaced therefrom. An axial opening in the interiorwall abuts the bottom end of the tubular filter element. The connectingend caps can be machined to have aligned input and output ports and/orinput and output ports at right angles to each other.

These and other advantages of the present invention will be clarified inthe Description of the Preferred Embodiments taken together with theattached figures wherein like reference numerals represent like elementsthroughout.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, advantages, and features of the present invention will bemore clearly understood from the following detailed description whentaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a top plan view of one embodiment of a one-piece input end capof a filter according to the present invention;

FIG. 2 is a sectional view of the one-piece input end cap taken alongline A-A of FIG. 1;

FIG. 3 is a bottom plan view of the one-piece input end cap of FIG. 1;

FIG. 4 is a schematic side view of a second filtration system utilizinga filter of FIG. 15;

FIG. 5 is a bottom plan view of the filter with a sensor removed fromthe filtration system illustrated in FIG. 4;

FIG. 6 is a top view of a modified version of the filter illustrated inFIG. 4;

FIG. 7 is a top plan view of a modified version of the filterillustrated in FIG. 4;

FIG. 8-A is a top plan schematic view of a filtration system utilizingtwo filters of FIG. 15 placed in series and illustrating the availableporting options;

FIG. 8-B is a schematic side view of the system of FIG. 8-A;

FIG. 9-A is a top plan schematic view of a filtration system utilizingtwo filters of FIG. 15 placed in series and illustrating the availableporting options;

FIG. 9-B is a schematic side view of the system of FIG. 9-A;

FIG. 10-A is a top plan schematic view of a filtration system utilizingtwo filters of FIG. 15 placed in series and illustrating the availableporting options;

FIG. 10-B is a schematic side view of the system of FIG. 10-A;

FIG. 11-A is a top plan schematic view of a filtration system utilizingthree filters of FIG. 15 placed in series and illustrating the availableporting options;

FIG. 11-B is a schematic side view of the system of FIG. 11-A;

FIG. 12-A is a top plan schematic view of a filtration system utilizingthree filters of FIG. 15 placed in series and illustrating the availableporting options;

FIG. 12-B is a schematic side view of the system of FIG. 12-A;

FIG. 13-A is a top plan schematic view of a filtration system utilizingthree filters of FIG. 15 placed in series and illustrating the availableporting options;

FIG. 13-B is a schematic side view corresponding to FIG. 13-A of threefilters placed in series and parallel simultaneously according toanother embodiment of the present invention;

FIG. 14 is a portable filter according to another-embodiment of thepresent invention;

FIG. 15 is a perspective schematic view of a filtration system utilizingfilters according to another embodiment of the present invention; and

FIG. 16 is a perspective view of a filter element utilized in thefilters of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 15 schematically illustrates a filtration system 10 utilizingindividual filters based upon a one-piece input end cap according to thepresent invention. The one-piece input end cap provides for flexibilityin placement and utility in numerous design configurations with existingequipment. The one-piece input end cap provides multiple portingoptions, mounting options, and sensor placements for a variety offiltration system configurations, such as the system 10. The filters ofthe present invention will decrease design time, engineering costs,manufacturing costs, and inventory for the system 10 as well as provideother advantages as will be herein described.

The system 10, schematically illustrated in FIG. 15, includes filterspositioned immediately adjacent and mounted directly to each other asherein described. The filters can be connected to each other in seriesor in parallel as will be described, and can be secured to a floor ormounting member 12. The system 10 additionally includes a pump 14 fordirecting fluid through the individual filters and is controlled throughthe controls found in the control box 16. The pump 14 is connected withthe filters through hydraulic chambers (not shown for clarity).Additionally, a differential pressure sensor 18, or other sensor, can beprovided in a stand-alone fashion on the input or the output lines fromthe filters. The filters may also include sensors as will be described.The mounting member 12 additionally could have a raised manifold at area20 to which the filters are attached. The provision of the raisedmanifold at area 20 allows the hydraulic input and output chambers, ifdesired, to be connected to the various filters through the manifoldfrom beneath the filters, as will be described in greater detailhereinafter.

The individual filters of the system 10 can be connected directly toeach other in series or connected in parallel, depending on theparticular application. Each filter includes a closed end cap 30, whichis attached via threads or otherwise secured to a canister 40, whichextends along a longitudinal axis 42. The canister 40 can also bereferred to as a filtration canister or a housing unit. The canister 40and closed end cap 30 form a container or chamber for holding areplaceable filter element 44, which is shown separately in FIG. 16. Awide variety of replaceable filter elements 44, such as those sold bySchroeder Industries, can be utilized depending on the particularapplication. The individual filter element 44 may be formed, forexample, from the EXCELLEMENT® series filter element, the ESAFE® StandAlone Disposable Element, or even the CORECENTRIC® Coreless element, allsold by Schroeder Industries. These are representative-type elementsthat can be easily incorporated in a particular grade and would bedetermined based upon the flow rate and the cleanliness level desiredand other associated factors with the particular application as isunderstood by those skilled in the art.

In particular, a feature for the filter of the present invention is theprovision of a one-piece input end cap 50 secured to the canister 40.The one-piece input end cap 50 is modular in nature so as to allowflexibility in arrangement and connection as will be described infurther detail herein below. The one-piece input end cap 50 illustratedin the filter is a base since the filters illustrated in FIG. 15 arebase-ported filters. The one-piece input end cap 50 of the presentinvention can also be utilized as top ported filters or wall-mountedfilters. Essentially, for top-ported filters, the filters illustrated inFIG. 15 would be inverted with the one-piece input end cap 50 located onthe top and the closed end cap 30 located on the bottom. In thisarrangement, the closed end cap 30 would be pinned to the canister 40for removal and replacement of the filter element 44.

In replacing the filter element 44 in the filter, the closed end cap 30is removed from the canister 40, typically by unthreading the closed endcap 30 to gain access to the interior. With the closed end cap 30removed from the canister 40, the filter element 44 is pulled out andreplaced with a new filter element 44, and the closed end cap 30 isreattached to the canister 40. In the top-ported configuration, theclosed end cap 30 is pinned to the canister 40, such that rotation ofthe closed end cap 30 will also rotate the canister 40 and remove boththe canister 40 and closed end cap 30 together with the attached filterelement 44 for replacement of the filter element 44. The filter element44 will be removed, a new filter element 44 positioned in the canister40, and pinned closed end cap 30 then screwed into the top-portedone-piece input end cap 50.

The one-piece input end cap 50 is shown in greater detail in FIGS. 1-3.Turning to FIG. 2, the upper neck portion of the one-piece input end cap50 includes a cylindrical member 52 defining a cylindrical axis andhaving internal threads 53 for attachment to the canister 40. Below theinternal threads 53 of the cylindrical member 52 is an O-ring groove 54,or other sealing member. The O-ring groove 54 would typically be forreceipt of an O-ring sealing between the canister 40 and the one-pieceinput end cap 50. The one-piece input end cap 50 includes an inputchamber 56 and an output chamber 58 positioned adjacent the filterelement 44 and in fluid communication with the filter element 44, asunderstood in the art. If an out/in filter element is used, the inputchamber must communicate with the outside of the filter element, and theoutput chamber must communicate with the inside of the filter element.

The filter element 44 will seal against the input chamber 56 and outputchamber 58. Preferably, in an out/in filter element, the central openingof the tubular filter element 44 will seal against the output chamber58, and the outside of the filter element 44 will be in contact with theinput chamber 56. Hydraulic ports 60, 62 extend into the one-piece inputend cap 50 and are in communication with the input chamber 56 and outputchamber 58, respectively. The hydraulic port 60 combines with the inputchamber 56 to form a hydraulic input chamber extending to and in fluidcommunication with the filter element 44. In a similar fashion, thehydraulic port 62 extends to the output chamber 58 to form a hydraulicoutput chamber extending from the filter element 44.

As shown in FIGS. 1 and 3, the one-piece input end cap 50 includesbosses 64, 66 on opposed sides thereof. The bosses 64, 66 allow for theplacement of the hydraulic ports 60, 62, respectively, and may besquare, rectangular, or circular as desired.

The one-piece input end cap 50 additionally includes two rectangularmounting plates or flanges 70, 72 on the sides thereof which extend theentire width of the one-piece input end cap 50. The mounting flanges 70,72 are parallel to each other and essentially form an I-beam or H-beamconfiguration for the modular one-piece input end cap 50. Additionally,as illustrated in FIGS. 1-2, the perimeter or plan view of the one-pieceinput end cap 50 is substantially a square. In other words, the width orlength of the mounting flanges 70, 72 substantially equal the distancebetween the mounting flanges 70, 72. The square configuration and themounting flanges 70, 72 combine to allow a side-to-end attachment ofadjacent filters in addition to the more conventional side-to-sideattachment. The mounting flanges 70, 72 provide multiple attachingpurposes for the individual applications.

The one-piece input end cap 50 additionally includes structural webbing74 extending between the mounting flanges 70, 72 on the sides of theone-piece input end cap 50 and the bosses 64, 66 on the ends. Themounting flanges 70, 72 are primarily for attachment of the filters toadjacent filters and/or attachment of the filters to vertical surfacesin a freestanding manner, such as a wall, or a base structure, such as amanifold. For attachment of the modular one-piece input end cap 50 andassociated filters to the manifold area, the mounting flanges 70, 72 maybe provided with threaded tap holes 76. The threaded tap holes 76 canreceive studs for mounting the one-piece input end cap 50 in position.Additionally, as illustrated in FIG. 1, adjacent filters can bepositioned next to each other with the mounting flange 70 or 72positioned adjacent the end (for example, including the bosses 64, 66)of the adjacent filter in a side-to-end attachment. In general, inmounting adjacent filters in series, the mounting flange 70 or boss 66of an upstream filter would be next to the boss 64 or the mountingflange 72 of an adjacent downstream filter. In any modular one-pieceinput end cap 50, the mounting flange 72 and boss 64 are adjacent theinput chamber 56, and the mounting flange 70 and boss 66 are adjacentthe output chamber 58. The square configuration allows for theend-to-side attachment and allows the units to be secured together by abolt extending through one mounting flange 70, 72 into the end face ofan adjacent mounting flange 70, 72 as illustrated in FIG. 15.Additionally, the mounting flanges 70, 72 essentially form the H- orI-beam configuration to give the necessary access for attaching adjacentfilters in a simple fashion.

A key feature of the present invention is the multiple porting optionsoffered by the present invention. In particular, the hydraulic ports 60,62 need not be positioned in the bosses 64, 66. As shown in FIGS. 1 and3, both the input chamber 56 and the output chamber 58 are generallykidney-shaped chambers extending more than 90 degrees around the axis ofthe cylindrical member 52. Consequently, the input chamber 56 can beaccessed by the hydraulic port 60 positioned in either the boss 64, themounting flange 72, or in the bottom of the modular one-piece input endcap 50. As shown in FIG. 3, the mounting flange 72 is positionedadjacent the input chamber 56. In a similar fashion, the hydraulic port60 can alternatively extend into the input chamber 56 from the bottom ofthe one-piece input end cap 50 in a direction extending along thelongitudinal axis 42 of the filtration canister 40. Essentially, theinput chamber 56 allows the input hydraulic port 60 to extend into theone-piece input end cap 50 from any of three mutually perpendiculardirections as desired by the user. In a similar fashion, the outputhydraulic port 62 can be positioned to extend from the modular one-pieceinput end cap 50 from any of three mutually perpendicular directionsincluding the longitudinal axis 42 of the canister 40.

This modular configuration is a key feature of the present invention,allowing the single modular one-piece input end cap 50 to be utilized ina wide variety of design applications. For example, there areeffectively nine separate configurations that are possible for modularone-piece input end cap 50 having one inlet hydraulic port 60 and oneoutlet hydraulic port 62. Multiple configurations can further beobtained when the modular one-piece input end cap 50 is rotated 90°,180°, and 270°. Additional modifications can include the provision ofmultiple inlet and/or multiple outlet hydraulic ports provided in any ofthe three mutually perpendicular directions described. In consideringfiltration systems of multiple filters in series or in parallel,multiple mounting options and respective positioning provide numerousoptions for easily adapting the system 10 to environmental limitations.

The location and direction of the hydraulic ports 60, 62 are drivenlargely by the design configurations of the particular system. Forexample, where the filters are to be utilized in series, the output ofthe first filter may position the hydraulic port 62 in the mountingflange 70, which will be attached to an adjacent modular one-piece inputend cap 50 which may position the input hydraulic port 60 in the boss 64connected directly to the adjacent modular one-piece input end cap 50.The mounting flanges 70, 72 and bosses 64, 66 are adapted for directface-to-face connection with either the bosses 64, 66 or mountingflanges 70, 72 of an adjacent modular one-piece input end cap 50 toprevent subsequent hydraulic coupling lines being necessary forattaching adjacent filters. Another advantage of the present inventionis that the series of adjacent filters need not extend in a continuousline but, due to the square configuration, can extend in a perpendiculardirection to each other.

FIGS. 8-A-13-B illustrate the different porting combinations andmounting options available that can be achieved as described above.FIGS. 8-A-10-B show filtration systems with two of the filters of thepresent invention in series with the inlet and outlet porting optionsillustrated. FIGS. 8-A and 8-B illustrate a side-to-end configurationwith the corresponding porting options. FIGS. 9-A and 9-B illustrate aside-to-side configuration. FIGS. 10-A and 10-B illustrate anend-to-side configuration. The distinctions between FIGS. 8-A-10-B arethe available porting options and the different mounting options forsecuring the respective system 10 to its environment. It should beunderstood that the porting options also illustrate the possible sensorlocations which may also affect the desired filtration system. FIGS.11-A-13-B illustrate some of the porting combinations and mountingcombinations available when three filters are placed in series. FIG.11-A illustrates a side-to-end-to-side configuration with correspondingporting options. FIG. 12-A illustrates a side-to-side-to-sideconfiguration. Note FIG. 13-A-13-B illustrate the perpendiculararrangement of a block of three or more filters in a system 10. Again,the distinctions between FIGS. 11-A-13-B are made to illustrate theavailable porting options and the different mounting options forsecuring the respective system 10 in its environment.

As shown in FIG. 1, the modular one-piece input end cap 50 easilyaccommodates conventional bypass valve ports 80 which will communicatewith the output chamber 58, as known in the art. The number of bypassvalve ports 80 is typically selected based upon the desired flowthrough.

FIG. 4 illustrates another system 10 utilizing a filter according to thepresent invention. The filter has a closed end cap 30, canister 40,filtration element 44 (not shown), and modular one-piece input end cap50. Additionally, the modular one-piece input end cap 50 of the presentinvention allows for easy placement of a sensor, such as a differentialpressure sensor 18 in the modular one-piece input end cap 50. Thedifferential pressure sensor 18 will be typically positioned incommunication with the input chamber 56. However, sensors may also beprovided on the output chamber 58 in communication with the outputchamber 58. The differential pressure sensor 18 essentially requires anindicator port 84 to communicate with the input chamber 56. As with theposition of the input hydraulic port 60, the differential pressuresensor 18 can be provided in any one of three mutually perpendiculardirections on the input chamber 56 as well as any of three mutuallyperpendicular directions on the output chamber 58. This allows greatflexibility in the position of sensors in the filter according to thepresent invention. For example, FIGS. 5-7 show alternative locations forthe differential pressure sensor 18 within the present invention. Theembodiment illustrated in FIGS. 4-7 additionally shows the ease ofincorporation of a drain plug 86 in the modular one-piece input end cap50 of the present invention or another differential pressure sensor 18on the end cap 30 in the filter of the present invention. The modularone-piece input end cap 50 maintains all of the porting options.

FIG. 14 illustrates another system 10 according to the present inventionin which the filter is formed as a portable system 10. Here, pump 14 ismounted to a mounting member 12, which is movable with the wheels 88 andthe handle 90. In this embodiment, the one-piece input end cap 50 ismolded integrally with a manifold 92 extending directly to the pump 14.This embodiment is merely intended to show the flexibility of theone-piece input end cap 50 of the present invention which can beutilized and molded for a particular application with minimalengineering modifications.

Thus, the present invention adds a degree of modularity for designingfiltration systems by allowing adjacent filters to be directly attachedto each other in a variety of configurations. This can be done byallowing the modular one-piece input end cap to be utilized as abase-ported filter or a top-ported filter. While not all the mountingoptions are described herein, the modular one-piece input end cap isdesigned to allow for maximum flexibility, for example, wall mounting,top porting and base porting. In addition, the modular one-piece inputend cap is designed to have the porting options which come in and go outof any three mutually perpendicular directions, as well as to havesensors mounted in any one of three mutually perpendicular directions.Another feature of the modular one-piece input end cap is that of the H-or I-beam shape which allows for the necessary structural and forside-to-side or side-to-end attachment configurations. The use of thepresent invention simplifies the engineering design process. System costhas substantially decreased as will be appreciated by the manufacturerand contractor/end user. The present invention allows for theflexibility and adaptability of a hydraulic filter that can be placed invarious system configurations and different environments.

The particular embodiments illustrated in the present application areintended to be illustrative of the present invention and not restrictivethereof. It would be obvious to one of ordinary skill in the art thatvarious modifications may be made to the present invention withoutdeparting from the spirit and scope thereof. The scope of the presentinvention is intended to be defined by the appended claims andequivalents thereto.

The invention claimed is:
 1. A filter comprising: a mounting structure;a pump mounted on the mounting structure; a canister supported on themounting structure and extending along a longitudinal axis; a closed endcap supported on the mounting structure and positioned at one end of thecanister attached to the canister for closing one end thereof; aremovable filter element contained within the canister; and a modularone-piece input end cap at an opposite end of the canister from theclosed end cap, the one-piece input end cap attached to the canister,wherein the one-piece input end cap includes a hydraulic input chamberextending to the filter element, a manifold extending directly from aside of the end cap to the pump, wherein the manifold and the end capare formed as one-piece, wherein the one-piece input end cap includes ahydraulic output chamber extending from the filter element, and whereinthe end cap is configured to be ported to form outlet ports leading fromthe hydraulic output chamber in any of at least two mutuallyperpendicular directions.
 2. The filter of claim 1, wherein theone-piece input end cap includes a pair of substantially rectangularmounting flanges on opposite sides of the one-piece input end cap. 3.The filter of claim 2, wherein the one-piece input end cap includes aboss on the one-piece input end cap, wherein the boss is located in aposition substantially perpendicular to the mounting flanges.
 4. Thefilter of claim 2, wherein the one-piece input end cap includes aninternally threaded cylindrical member for attaching the canisterthereto.
 5. The filter of claim 2, wherein the one-piece input end capis a base for the filter.
 6. The filter of claim 1, wherein theone-piece input end cap includes a boss formed on a side of the end capthat is adjacent the hydraulic output chamber of the one-piece input endcap.
 7. The filter of claim 6, wherein the one-piece input end capincludes a pair of substantially rectangular mounting flanges.
 8. Thefilter of claim 6, wherein one of the rectangular mounting flanges isformed on a side of the end cap that is adjacent the hydraulic inputchamber of the one-piece input end cap and the other of the rectangularmounting flanges is formed on a side of the end cap that is adjacent thehydraulic output chamber of the modular one-piece input end cap.
 9. Thefilter of claim 1, further including wheels coupled to and supportingthe mounting structure.
 10. The filter of claim 9, further including ahandle coupled to the mounting structure.
 11. The filter of claim 10,wherein the one-piece input end cap includes a pair of substantiallyrectangular mounting flanges.
 12. The filter of claim 11, wherein one ofthe rectangular mounting flanges is formed on a side of the end cap thatis adjacent the hydraulic input chamber of the one-piece input end capand the other of the rectangular mounting flanges is formed on a side ofthe end cap that is adjacent the hydraulic output chamber of the modularone-piece input end cap.
 13. The filter of claim 11, wherein theone-piece input end cap includes a boss formed on a side of the end capthat is adjacent the hydraulic output chamber of the one-piece input endcap.
 14. The filter of claim 10, wherein the one-piece input end capincludes a boss formed on a side of the end cap that is adjacent thehydraulic output chamber of the one-piece input end cap.